<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body></body>
  <script>
    let a = {
      name: 'Julia',
      age: 20,
    };
    function change(o) {
      o.age = 24;
      o = {
        name: 'Kath',
        age: 30,
      };
      return o;
    }
    let b = change(a);
    console.log(b.age);
    console.log(a.age);
  </script>
</html>
